Ton had also said defence cooperation is one of the important and effective areas of cooperation between India and Vietnam and India can be helpful in expanding Vietnam’s defence capabilities.

Reacting to Ton’s remarks, Chinese Foreign Ministry spokesperson Lu Kang said that Beijing will oppose any attempt to infringe upon its legitimate rights.

“China does not object to the development of normal bilateral relations of relevant countries in our neighbourhood but we firmly oppose relevant party to use it is an excuse to infringe upon China’s legitimate rights and impair regional peace and stability,” Lu Kang said.

Vietnam is one the claimants of the South China Sea, of which 90% is claimed by China. The Philippines, Taiwan, Malaysia and Brunei also have overlapping claims to the energy-rich waters.

The Vietnamese envoy said Hanoi was within its legal rights to invite India and will welcome port calls by Indian Navy in the waters.

India’s ONGC Videsh Ltd, the overseas arm of Oil and Natural Gas Corp, is already engaged in exploration in the 128 basin of the South China Sea controlled by Vietnam.

China has been opposing ONGC exploring oil in wells claimed by Vietnam in the South China Sea (SCS) for years. India has been asserting that the ONGC's exploration is a commercial operation and not connected with the dispute.